Time-lapse photography is a technique whereby the frequency at which film frames are captured (the frame rate) is much lower than that used to view the sequence. When played at normal speed, time appears to be moving faster and thus lapsing. For example, an image of a scene may be captured once every second, then played back at 30 frames per second; the result is an apparent 30 times speed increase. Time-lapse photography can be considered the opposite of high speed photography or slow motion.

Processes that would normally appear subtle to the human eye, e.g. the motion of the sun and stars in the sky, become very pronounced. Time-lapse is the extreme version of the cinematography technique of undercranking, and can be confused with stop motion animation.

The technique has been used to photograph crowds, traffic, and even television. The effect of photographing a subject that changes imperceptibly slowly, creates a smooth impression of motion. A subject that changes quickly is transformed into an onslaught of activity.

The first use of Lapse-Time to record the movement of flowers took place in Yosemite in late 1911–1912 by Arthur C. Pillsbury, who built a special camera for this purpose and recorded the movements of flowers through their life cycle.[citation needed] Pillsbury owned the Studio of the Three Arrows in the Valley and applied the technique to solving the problem of ensuring the survival of the rapidly shrinking varieties in the meadows. The Cavalry, then in charge of Yosemite, were mowing the meadows to produce fodder for their horses.

Pillsbury showed his first film to Superintendents for the National Parks during a conference held for them in Yosemite from October 14–16, 1912. The result was a unanimous agreement by the Superintendents to cease cutting the meadows and begin preservation. Pillsbury made lapse-time movies for 500 of the 1,500 varieties of wildflowers in Yosemite over the next years.

His films were shown during his lectures, which were scheduled first at garden clubs around California and then at most of the major universities across the country. Pillsbury also showed his films and lectured to town hall forums and the National Geographic Society.

In 1926 he was asked to present both his lapse-time motion pictures and his newly invented microscopic film to President Calvin Coolidge at a dinner given on March 15 in the President's honor at the Willard Hotel in Washington DC. Pillsbury had been invited to present the films by Secretary of the Interior Herbert Work.

The use of photography in this form to obtain the preservation of natural resources was a first and followed his use of film to make the first recorded nature movie, shown to tourists in Yosemite in the spring of 1909.

From 1929 to 1931, R. R. Rife astonished journalists with early demonstrations of high magnification time-lapse cine-micrography[4][5] but no filmmaker can be credited for popularizing time-lapse more[citation needed] than Dr. John Ott, whose life-work is documented in the DVD-film Exploring the Spectrum.

Ott's initial "day-job" career was that of a banker, with time-lapse movie photography, mostly of plants, initially just a hobby. Starting in the 1930s, Ott bought and built more and more time-lapse equipment, eventually building a large greenhouse full of plants, cameras, and even self-built automated electric motion control systems for moving the cameras to follow the growth of plants as they developed. He time-lapsed his entire greenhouse of plants and cameras as they worked – a virtual symphony of time-lapse movement. His work was featured on a late 1950s episode of the request TV show, You Asked For It.

Ott discovered that the movement of plants could be manipulated by varying the amount of water the plants were given, and varying the color-temperature of the lights in the studio. Some colors caused the plants to flower, and other colors caused the plants to bear fruit. Ott discovered ways to change the sex of plants merely by varying the light source color-temperature.

By using these techniques, Ott time-lapse animated plants "dancing" up and down in synch to pre-recorded music tracks.

His cinematography of flowers blooming in such classic documentaries as Walt Disney's Secrets of Life (1956), pioneered the modern use of time-lapse on film and television.[citation needed] Ott wrote several books on the history of his time-lapse adventures, My Ivory Cellar (1958), Health and Light (1979), and the film documentary Exploring the Spectrum (DVD 2008).

PBS's NOVA series aired a full episode on time-lapse (and slow motion) photography and systems in 1981 titled Moving Still. Highlights of Oxford's work are slow-motion shots of a dog shaking water off himself, with close ups of drops knocking a bee off a flower, as well as time-lapse of the decay of a dead mouse.

The first major usage of time-lapse in a feature film was Koyaanisqatsi (1983).[citation needed] The non-narrative film, directed by Godfrey Reggio, contained time-lapse of clouds, crowds, and cities filmed by cinematographer Ron Fricke. Years later, Ron Fricke produced a solo project called Chronos shot on IMAX cameras, which is still frequently played on Discovery HD. Fricke used the technique extensively in the documentary Baraka (1992) which he photographed on Todd-AO (70 mm) film. Recent films made entirely in time-lapse photography include Nate North's film, Silicon Valley Timelapse, which holds the distinction of being the first feature-length film shot almost entirely in 3 frame high dynamic range, as well as artist Peter Bo Rappmund's three feature-length documentaries, Psychohydrography (2010), Tectonics (2012), and Topophilia (2015).

Countless other films, commercials, TV shows and presentations have included time-lapse.

The frame rate of time-lapse movie photography can be varied to virtually any degree, from a rate approaching a normal frame rate (between 24 and 30 frames per second) to only one frame a day, a week, or longer, depending on subject.

The term "time-lapse" can also apply to how long the shutter of the camera is open during the exposure of each frame of film (or video), and has also been applied to the use of long-shutter openings used in still photography in some older photography circles. In movies, both kinds of time-lapse can be used together, depending on the sophistication of the camera system being used. A night shot of stars moving as the Earth rotates requires both forms. A long exposure of each frame is necessary to enable the dim light of the stars to register on the film. Lapses in time between frames provide the rapid movement when the film is viewed at normal speed.

As the frame rate of time-lapse approaches normal frame rates, these "mild" forms of time-lapse are sometimes referred to simply as fast motion or (in video) fast forward. This type of borderline time-lapse resembles a VCR in a fast forward ("scan") mode. A man riding a bicycle will display legs pumping furiously while he flashes through city streets at the speed of a racing car. Longer exposure rates for each frame can also produce blurs in the man's leg movements, heightening the illusion of speed.

Two examples of both techniques are the running sequence in Terry Gilliam's The Adventures of Baron Munchausen (1989) in which Eric Idle outraces a speeding bullet, and Los Angeles animator Mike Jittlov's 1980 short and feature-length film, both titled The Wizard of Speed and Time, released to theaters in 1987 and to video in 1989. When used in motion pictures and on television, fast motion can serve one of several purposes. One popular usage is for comic effect. A slapstick style comic scene might be played in fast motion with accompanying music. (This form of special effect was often used in silent film comedies in the early days of the cinema; see also liquid electricity).

Another use of fast motion is to speed up slow segments of a TV program that would otherwise take up too much of the time allotted a TV show. This allows, for example, a slow scene in a house redecorating show of furniture being moved around (or replaced with other furniture) to be compressed in a smaller allotment of time while still allowing the viewer to see what took place.

The opposite of fast motion is slow motion. Cinematographers refer to fast motion as undercranking since it was originally achieved by cranking a handcranked camera slower than normal. Overcranking produces slow motion effects.

Film is often projected at 24 frame/s, meaning 24 images appear on the screen every second. Under normal circumstances, a film camera will record images at 24 frame/s. Since the projection speed and the recording speed are the same, the images onscreen appear to move at normal speed.

Even if the film camera is set to record at a slower speed, it will still be projected at 24 frame/s. Thus the image on screen will appear to move faster.

The change in speed of the onscreen image can be calculated by dividing the projection speed by the camera speed.

So a film recorded at 12 frames per second will appear to move twice as fast. Shooting at camera speeds between 8 and 22 frames per second usually falls into the undercranked fast motion category, with images shot at slower speeds more closely falling into the realm of time-lapse, although these distinctions of terminology have not been entirely established in all movie production circles.

The same principles apply to video and other digital photography techniques. However, until very recently[when?], video cameras have not been capable of recording at variable frame rates.

Time-lapse can be achieved with some normal movie cameras by simply shooting individual frames manually. But greater accuracy in time-increments and consistency in exposure rates of successive frames are better achieved through a device that connects to the camera's shutter system (camera design permitting) called an intervalometer. The intervalometer regulates the motion of the camera according to a specific interval of time between frames. Today, many consumer grade digital cameras, including even some point-and-shoot cameras have hardware or software intervalometers available. Some intervalometers can be connected to motion control systems that move the camera on any number of axes as the time-lapse photography is achieved, creating tilts, pans, tracks, and trucking shots when the movie is played at normal frame rate. Ron Fricke is the primary developer of such systems, which can be seen in his short film Chronos (1985) and his feature films Baraka (1992, released to video in 2001) and Samsara (2011).

As mentioned above, in addition to modifying the speed of the camera, it is important to consider the relationship between the frame interval and the exposure time. This relationship controls the amount of motion blur present in each frame and is, in principle, exactly the same as adjusting the shutter angle on a movie camera. This is known as "dragging the shutter".

A film camera normally records images at twenty four frames per second. During each 1/24th of a second, the film is actually exposed to light for roughly half the time. The rest of the time, it is hidden behind the shutter. Thus exposure time for motion picture film is normally calculated to be one 48th of a second (1/48 second, often rounded to 1/50 second). Adjusting the shutter angle on a film camera (if its design allows), can add or reduce the amount of motion blur by changing the amount of time that the film frame is actually exposed to light.

Blurring vs. exposure times

In time-lapse photography, the camera records images at a specific slow interval such as one frame every thirty seconds (1/30 frame/s). The shutter will be open for some portion of that time. In short exposure time-lapse the film is exposed to light for a normal exposure time over an abnormal frame interval. For example, the camera will be set up to expose a frame for 1/50th of a second every 30 seconds. Such a setup will create the effect of an extremely tight shutter angle giving the resulting film a stop-animation or claymation quality.

In long exposure time-lapse, the exposure time will approximate the effects of a normal shutter angle. Normally, this means the exposure time should be half of the frame interval. Thus a 30‑second frame interval should be accompanied by a 15‑second exposure time to simulate a normal shutter. The resulting film will appear smooth.

The exposure time can be calculated based on the desired shutter angle effect and the frame interval with the equation:

Long exposure time-lapse is less common because it is often difficult to properly expose film at such a long period, especially in daylight situations. A film frame that is exposed for 15 seconds will receive 750 times more light than its 1/50th of a second counterpart. (Thus it will be more than 9 stops over normal exposure.) A scientific grade neutral density filter can be used to compensate for the over-exposure.

Some of the most stunning time-lapse images are created by moving the camera during the shot. A time-lapse camera can be mounted to a moving car for example to create a notion of extreme speed.

However, to achieve the effect of a simple tracking shot, it is necessary to use motion control to move the camera. A motion control rig can be set to dolly or pan the camera at a glacially slow pace. When the image is projected it could appear that the camera is moving at a normal speed while the world around it is in time lapse. This juxtaposition can greatly heighten the time-lapse illusion.

The speed that the camera must move to create a perceived normal camera motion can be calculated by inverting the time-lapse equation:

The short film A Year Along the Abandoned Road shows a whole year passing by in Norway's Børfjord at 50,000 times the normal speed in just 12 minutes. The camera was moved, manually, slightly each day, and so the film gives the viewer the impression of seamlessly travelling around the fjord as the year goes along, each day compressed into a few seconds.

A variation of these are rigs that move the camera during exposures of each frame of film, blurring the entire image. Under controlled conditions, usually with computers carefully making the movements during and between each frame, some exciting blurred artistic and visual effects can be achieved, especially when the camera is mounted on a tracking system that enables its own movement through space.

The most classic example of this is the slit-scan opening of the stargate sequence toward the end of Stanley Kubrick's 2001: A Space Odyssey (1968), created by Douglas Trumbull.

One method using a DSLR involves bracketing for each frame. Three photographs are taken at separate exposure values (capturing the three in immediate succession) to produce a group of pictures for each frame representing the highlights, mid-tones, and shadows. The bracketed groups are consolidated into individual frames (see HDR). Those frames are then sequenced into video. Time Lapse is also used for travel videoclips where the viewer can experience a faster traveling speed than the normal one, for example, traveling from Los Angeles to New York in 5 minutes.

However, the number of images required to be taken is relatively high. For a 30 fps video of HDR (each frame tonemapped with 3 images), 5,400 original images (60×30×3) are required for each minute.

Cameras that support time-lapse still image capture with a built-in intervalometer[edit]